Issue Archive

Special Coverage

To realize the "Internet of things” — the idea that all parts of the human environment, from kitchen appliances to industrial equipment, could be equipped with sensors and processors that exchange data — transmitters must be energy-efficient enough to last for months.
A group researchers at the Massachusetts Institute of Technology (MIT) have developed a new transmitter design that reduces off-state leakage 100-fold. The design provides adequate power for Bluetooth transmission, or for the longer-range 802.15.4 wireless-communication protocol.
While semiconductors are not naturally very good conductors, neither are they perfect insulators. Even when no charge is applied to the gate, some current still leaks across the transistor.
The leakage is reduced by applying a negative charge to the gate when the transmitter is idle. The charge drives electrons away from the electrical leads, making the semiconductor a much better insulator.
In tests conducted on a prototype chip fabricated through the Taiwan Semiconductor Manufacturing Company’s research program, the MIT researchers found that their circuit spent only 20 picowatts of power to save 10,000 picowatts in leakage.
To generate the negative charge efficiently, the MIT researchers use a circuit known as a charge pump, which is a small network of capacitors — electronic components that can store charge — and switches. When the charge pump is exposed to the voltage that drives the chip, charge builds up in one of the capacitors. Throwing one of the switches connects the positive end of the capacitor to the ground, causing a current to flow out the other end.
Source
Also: Read other Electronics tech briefs.

Researchers at the University of California, Riverside’s Bourns College of Engineering have developed a novel paper-like material for lithium-ion batteries. The spongelike silicon nanofibers are 100 times thinner than human hair. The technology could be used in batteries for electric vehicles and personal electronics.The nanofibers were produced using a technique known as electrospinning, whereby 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate. The material is then exposed to magnesium vapor to produce the sponge-like silicon fiber structure.The researchers’ future work involves implementing the silicon nanofibers into a pouch cell format lithium-ion battery, which is a larger scale battery format that can be used in EVs and portable electronics.The technology has the potential to boost by several times the amount of energy that can be delivered per unit weight of the battery.SourceAlso: Learn about NASA's Power Generation & Storage technologies.

By analyzing such parameters as the force applied by key presses and the time interval between them, a new self-powered, non-mechanical, intelligent keyboard could provide a stronger layer of security for computer users. The self-powered device generates electricity when a user’s fingertips contact the multi-layer plastic materials that make up the device.

A new underwater robot designed by University of Washington researchers will monitor the effects of tidal and wave energy on marine habitats.The instrument package has a range of technologies: a stereo camera to collect photos and video, a sonar system, hydrophones to hear marine mammal activity, sensors to gauge water quality and speed, a click detector to listen for whales, dolphins and porpoises, and a device to detect fish tags. A fiber optic cable connection back to shore allows for real-time monitoring and control, and the device will be powered by a copper wire.The instruments fit inside a remotely operated vehicle, or ROV, that can maneuver underwater and drop off the instrumentation package at a docking station integrated onto a turbine or other existing subsea infrastructure. The tool attaches to most types of underwater infrastructure, ranging from tidal turbines to offshore oil and gas rigs.Researchers outfitted the underwater surveying machine with five extra thrusters on an external frame to give it more power to move against strong currents. Actuators on the vehicle latch the monitoring instruments onto a subsea docking station, and then the robot can disengage, leaving the instruments in place, and travel back to the water’s surface.The team tested the vehicle, dubbed the"Millennium Falcon," and the instruments it transports, called the Adaptable Monitoring Package, underwater for the first time in January. UW will continue testing in Puget Sound under more challenging conditions starting this month.SourceAlso: Learn about Biologically Inspired Robots.

A NASA scientist, who has played a key role in developing and demonstrating a new technique for gathering carbon-dioxide (CO2) measurements, is applying the same general principles to develop a new laser instrument sensitive to another greenhouse gas, methane.A team, led by the NASA researcher Haris Riris, demonstrated a prototype Methane Sounder. The next-generation instrument will be able to provide remotely collected, high-resolution, highly accurate, around-the-clock global methane measurements should it ultimately fly as a spaceborne instrument. Although carbon dioxide, another greenhouse gas, lingers in the atmosphere longer, methane is in some respects more worrisome. It is more potent and effective at absorbing heat. Exacerbating concerns is the fact that large quantities of the gas reside beneath permanently frozen ground in the Arctic. As the permafrost melts, which scientists say currently is occurring, more of this gas is released into the atmosphere, creating a feedback mechanism, where emissions lead to more warming, which in turn accelerates the melting.Although some satellite instruments can detect and map Earth’s methane, Riris’ concept gives scientists something they don’t currently have — 24-hour coverage at all latitudes. In sharp contrast to many methane instruments, the Methane Sounder also employs its own light source — tunable laser transmitters. Although laser light cannot penetrate thick clouds, it can measure through thin clouds and particles and at night, which is impossible for passive systems that rely on reflected sunlight for their source of illumination.To gather methane data, the team’s instrument works much like the CO2 Sounder. The system bounces a laser light tuned to a specific wavelength band — in this case, 1.65 microns — off Earth’s surface. Like all atmospheric gases, methane will absorb the light as it travels back to the orbiting instrument. The more methane molecules along the path, the deeper the absorption lines as measured by the instrument’s detectors.SourceAlso: Learn about an Oxygen-Methane Thruster.

David Blake developed the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument that is currently deployed on the Mars Science Laboratory rover Curiosity. The powder-handling device inside CheMin won Blake the 2010 NASA Commercial Government Invention of the Year award. This technology allowed scientists to determine the quantitative mineralogy of the 3.5 billion-year-old rocks on the Red Planet for the first time.

A researcher at the Barcelona College of Industrial Engineering, in collaboration with the company Eolgreen, has developed the first autonomous industrialized public lighting system that works with solar and wind energy. This system, developed after four years of research, is designed for inter-urban roads, motorways, urban parks, and other public areas. It is unique in the world, and reduces the cost by 20% compared with conventional public lighting systems.
The prototype is 10 meters high and is fitted with a solar panel, a wind turbine, and a battery. The turbine runs at a speed of 10 to 200 rpm and has a maximum output of 400 watts. Work is being done on a second prototype generator that runs at a lower speed (10 to 60 rpm) and has a lower output (100 W). An electronic control system manages the flow of energy among the solar panel, the wind turbine, the battery, and the light.
Source:

Question of the Week

This week's Question: Last week, Elon Musk, chief executive of Tesla, said that the electric car maker would introduce autonomous technology, an autopilot mode, by this summer; the technology will allow drivers to have their vehicles take control...